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We aim to determine the analytical performance

of the Research-Use-Only (RUO) Xpert MRSA NxG using a frozen

samples biobank previously assayed by culture, Xpert MRSAGen3 RUO



A frozen library obtained in a previous study made of 155

nasal swabs discharged in saline (119 prospective and 36 swabs from

known MRSA culture positive patients) was screened with the new

RUO Cepheid Xpert MRSA NxG. 100μl of the suspension was assayed

on a GeneXpert IV platform. The same starting material had been

previously used for culture and molecular assays.


141 samples contained the required volume of 100μl. The

sensitivity and specificity of the Xpert MRSA NxG were 93.3% and

100%, respectively, while the positive and negative predictive values

were 100% and 96.9%, respectively. Three out of the 45 positive

samples tested were falsely negative and two unresolved. Suspensions

from four of these five isolates were appropriately detected by the

Xpert MRSA NxG assay.

Discussion and/or Conclusion(s):

The Xpert MRSA NxG proved to be

as effective as the previously released Xpert MRSA Gen3 while further

expanding the subtypes coverage, decreasing runtime from 77 to 70

minutes and providing room temperature storage and extended

shelf life.

ID: 4976

Why and how merge data by approximate string matching from a

prospective study and the DRG-based system to study the impact of

nosocomial infection

Joris Muller


, Pierre Tran Ba Loc


, Stéphanie Deboscker



Francis Schneider


, Thierry Lavigne




Strasbourg University Hospital;

Infection control and prevention unit,


Strasbourg University Hospital;

Public health service,


Strasbourg University Hospital; Medical intensive

care unit


Valuable data that could be used to perform original

studies are often split between multiple databases. However, linking

a manually fulfilled database with potential typing mistake with

another one is challenging.


Our objective was to develop an algorithm to link

two databases when no explicit linkage key exists.


Our algorithm calculates a

link likelihood score


between each pair of possible record in each database. The lower

this LLS is, the more probable the matching between the two records.

To take account of possible mistyping, this score was based on

Levensthein distances for non-numerical data and various calculations

for numerical data. We checked the accuracy by manually review 10%

of the non-perfect matching pairs and systematically when the score

was over a threshold. The algorithm was implemented in the open-

source R software.

We applied this method by linking data from a prospective study


database about nosocomial infection in the intensive care unit (REA-

RAISIN) with our local DRG system.


Among the 7479 records of our database, almost all

observations (99.8%) were linked with related records in the DRG-

based database. Without our algorithm only 5448 (72.8%) with a

perfect matching would be linked. No linking error was found when

the LLS was under the threshold. Among the 134 record manually

reviewed with a LLS above the threshold, only 14 (0.2%) were excluded

due to the lack of matching record between the databases.

Discussion and/or Conclusion(s):

This original algorithm implemen-

ted in a free software could be adapted to link potentially any other


ID: 4996

Extra-pulmonary tuberculosis: an epidemiological review of 90

cases at a London teaching hospital

Mary Peirse, Daniela Kirwan, Angela Houston.

St George

s University

Hospital NHS Foundation Trust


TB remains a major global health problem: an estimated

9.6 million new cases were reported worldwide in 2014. In England

47.1% of new cases reported in 2014 were extra-pulmonary (EPTB); this

proportion has increased since 2005. EPTB symptoms are often non-

specific, making diagnosis challenging.


This study aimed to retrospectively review

clinical and microbiological characteristics of all cases of EPTB

managed over a two-year period at a tertiary referral centre in

London, and compare with national data.


Since 2013, data from all inpatients attending the Clinical

Infection Unit at St. George

s Hospital have been entered into a

database. This was searched for patients treated for EPTB between

2013 and 2015. Parameters including site of disease, microbiological

confirmation, resistance pattern, and HIV status were collected.


A total of ninety cases were identified. Median age was 38

years (IQR 27

57 years) and 58 (64%) were male. The commonest

site was the lymph node (25%) followed by CNS disease (23%):

national figures are 42.2% and 4.5% respectively. A confirmed

microbiological diagnosis (positivity by automated liquid culture

and/or Xpert


MTB/RIF) was obtained in 69%. Five (8%) of these

patients had MDR-TB. 88 (98%) of patients had their HIV status

checked at diagnosis; 6 patients (7%) were HIV-positive, including 3

new diagnoses.

Discussion and/or Conclusion(s):

Inpatients treated for EPTB at St


s Hospital during the study period were mainly men of

working age, in keeping with national data. Almost a quarter had CNS

disease. The majority of patients were HIV-negative and MDR-TB rates

were low.

ID: 4999

Estimating the burden of group B streptococcal (GBS) maternal

sepsis in England

Theresa Lamagni, Rebecca Guy, Catherine Wloch, Nandini Shetty,

Vicki Chalker, Alan Johnson.

Public Health England


With encouraging progress in GBS vaccine development,

attention is increasingly focusing on identifying the breadth of

potential target groups for immunisation.


Our study aimed to quantify the incidence of GBS

sepsis associated with pregnancy and childbirth.


Laboratory confirmed GBS infections diagnosed from

normally sterile sites (invasive GBS disease, iGBS) in England in 2014

were extracted from national surveillance data (SGSS). Records were

linked to HSCIC Hospital Episode Statistics using NHS number and

analysed to identify pregnancy or childbirth within 6 weeks of GBS

diagnosis. Cases were compared to normative data on maternities

from ONS and HSCIC.


Of 1601 patients diagnosed with iGBS infection in England in

2014, 1546 (97%) were successfully linked to a hospital admission

record. Of these,185 (12%) were identified as maternal infections, 0.28/

1000 maternities. The median age of maternal cases was 30y (18


Seven cases were associated with miscarriage. Of 168 cases with

information on the interval between diagnosis and delivery, 74% (124)

were diagnosed on the day of delivery, 10% (16) antepartum and 17%

(28) postpartum. Of the 140 intra/antepartum infections, 41% were

emergency C-section deliveries. Although the proportion of preterm

(<37 week) deliveries was similar between cases and national data (7%


8%), a higher proportion of stillbirths were associated with maternal

GBS infection, 3%


0.47% (p < 0.001).

Discussion and/or Conclusion(s):

Our study identified a substantial

burden of maternal GBS infection with an associated higher risk of

stillbirth. Prevention of maternal infection should be a priority for

future public health strategy.

Abstracts of FIS/HIS 2016

Poster Presentations / Journal of Hospital Infection 94S1 (2016) S24